Would-be jihadi fighters are increasingly booking tickets on cruise ships to join extremists in battle zones in Syria and Iraq, hoping to bypass stepped-up efforts to thwart them in neighboring Turkey, Interpol officials have told The Associated Press.

This is one of the reasons why the international police body is preparing to expand a pilot program known as I-Checkit, under which airlines bounce passenger information off Interpol’s databases — in hopes that one day the system could expand to include cruise operators, banks, hotels and other private-sector partners.

Turkey, with its long and often porous border with Syria, has been a major thoroughfare for many of the thousands of foreign fighters seeking to join extremists like the Islamic State group, which has captured territory across Iraq and Syria.

Speaking in Monaco, where Interpol is holding its general assembly this week, outgoing chief Ronald Noble confirmed that Turkey was a destination, but declined to identify any others. He also refused to indicate how many people might be involved, but called on countries to step up screening at all transportation hubs — “airports and, more and more, cruise lines.”